This is a multidisciplinary clinical research program project which deals with new methods of diagnosis and treatment of cancer. Seven programs will be supported on this continuation application: Childhood ALL, New Morphologic Findings in Leukemia and Preleukemia, Biochemical Pharmacologic Studies of New Lipid Soluable Folate Antagonists, Mechanisms of Osteomalacia in Prostatic Cancer, An Immunology Reference Laboratory, Clinical and Laboratory Studies of Malignant Melanoma and Clinical Pathology and Corelative Studies in Breast Cancer.